In-line roller skate wheel and method of making same

ABSTRACT

A polyurethane in-line roller skate wheel including a narrow hub mounting a polyurethane tire body having side walls curving axially inwardly from a major thickness to a minor thickness at the hub flange interface. In one embodiment, the hub is made of sections locked together by either adhesive or mechanical interlocks.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an in-line roller skate wheel and a method and apparatus for its manufacture. More specifically, the present invention relates to a wheel having a urethane hub and solid urethane tire of a unique shape and the mold configuration required to cast the tire.

[0002] In-line roller skates have been in existence since the 18^(th) century, the first recorded having been constructed by a Dutchman who wanted to practice ice skating during warm weather by mounting wooden spools under his boots and skating on dry land. Other generally unsuccessful attempts at in-line roller skates followed but then, in the 19^(th) century, the four-wheel skate with two pairs of wheels in a rectangular configuration was developed and took over the skating world. In-line skates were used very sparingly, mostly by ice skaters for warm-weather cross-training. In the early 1980's, a pair of in-line skates was created and the concept greatly improved upon by a pair of ice hockey players who mounted polyurethane wheels under ice skating boots and, due to the vastly improved performance provided by these skates, the sport of in-line skating mushroomed. Along with increased popularity came the demand for even more improvements in performance and durability.

[0003] Today's in-line skaters include racers, roller hockey players, serious ice hockey players looking for a cross-training device, stunt skaters, and casual users who only desire exercise and a smooth ride. Manufacturers have developed wheels of various profiles and hardness values to enhance sliding, gripping, maneuverability, speed, comfort and durability depending on the user's desire and skill level. Large diameter wheels with minimal tire flexing to reduce rolling resistance are generally used when speed is desired. Smaller diameter wheels with shock absorbing properties are preferred for most recreational skating while those doing stunts such as rail slides require wheels of an even smaller diameter and high hardness value. Two popular types of wheels have emerged over the past two decades to meet these diverse needs, those containing pneumatic tires made by casting polyurethane around an annular bladder, and those with solid tires made by casting or injection molding polyurethane in the desired shape around a hard polyurethane or nylon hub.

[0004] Pneumatic tire designs have been proposed of a construction similar to automobile tires with a pneumatic bladder encapsulated in polyurethane. These wheels provide a cushioned ride and, containing less polyurethane, are generally lighter than a solid wheel. They provide good grip and shock absorbing properties and are very suited to use on uneven surfaces and when encountering rocks and other-road hazards. Although these wheels are well suited to these applications, they are generally more complex and expensive than solid tire wheels. U.S. Pat. Nos. 5,641,365, 6,085,815 and 6,102,091 to Peterson et al assigned to the assignee of the instant application and U.S. Pat. No. 5,853,225 to Huang disclose wheels of this type.

[0005] Solid tires are generally constructed of solid polyurethane tire bodies molded about a hub. Diameter, profile and hardness are adjusted for the skater's needs. U.S. Pat. No. 5,312,844 to Gonsior et al discloses a wheel with a thermoplastic polyether type polyurethane which is injection molded unto the hub to form a tire which is the width of the tire support ring at the ring contact radius and curves axially inwardly and radially outward to the tread surface. This shape tire is lacking in flexibility and ability to grip the ground during fast maneuvers. U.S. Pat. No. 5,567,019 to Raza et al discloses a similar wheel also with an injection molded tire of thermoplastic polyether type polyurethane and similar shape. Again, this shape tire is lacking in flexibility and ability to grip the ground during fast maneuvers. The manufacturing process is also relatively expensive.

[0006] U.S. Pat. No. 5,573,309 to Bekessy describes a wheel with a tapered tire deflection controlling rim extending circumferentially about the tire receiving shoulder, with rim side walls extending radially outward from a wide base at the tire receiving shoulder to a narrow peripheral surface. A resilient tire engages the tire receiving shoulder and encases the tapered tire deflection controlling rim. The tire includes an annular high friction shoulder situated radially inward and axially outward of its ground engaging outer surface. Deflection of this tire is said to allow use of more sidewall tire material for better compression and, in cooperation with the annular shoulder on the tire, cause progressively more tire material to contact the support surface as the skater turns, the harder the turn, the more surface contact for maintaining control. One configuration of this tire has recessed braking dimples situated about its ground engaging surface and radially inward of the tread section. The recessed braking dimples create channels of non-contact intended to reduce frictional resistance to a sideways skid when the skater is coming to a stop by tipping the skates to a maximum angle and skidding sideways to a stop. Although providing a good compromise between speed and gripping ability, the profile of this wheel is not optimized for weight reduction.

[0007] U.S. Pat. No. 5,655,784 to Lee discloses a solid tire mounted on a light weight fiber-reinforced hub to reduce flex and attain greater speed. U.S. Pat. No. 5,725,284 to Boyer discloses a wheel constructed of a plurality of layers of material disposed concentrically about a hub with the hardest material being on the outermost layer. U.S. Pat. No. 5,829,757 to Chiang et al discloses an in-line skate wheel with materials of similar hardness but different coefficient-of-friction values on different portions of the tires surface. The braking portion of the tire contains a high coefficient-of-friction material while the normal skating surface includes a high proportion of the low coefficient-of-friction material. This is touted as allowing the skater to proportionally engage the braking surface and control braking by leaning into the wheel and changing the angle to increase braking action.

[0008] These wheels each provide specific benefits but are generally complex, difficult to manufacture, and not optimized for high speed competition such as roller hockey and racing. There exists the need for a lightweight skate wheel which will provide a fast, smooth ride with excellent maneuverability and durability but without the complexity and expense of producing multi-segmented or pneumatic tires. There is also need to provide a method and apparatus for casting a wheel using a simple one piece tire, cast from urethane, and allowing use of unique profiles to reduce weight and enhance performance for any desired skating conditions.

SUMMARY OF THE INVENTION

[0009] The present invention includes many aspects. In one aspect it is in the form of a sculptured lightweight narrow in-line skate wheel particularly suited for, but not limited to, roller hockey and racing. The wheel includes a relatively hard, lightweight urethane hub and a solid urethane tire body with reduced hardness relative to the hub. The hub is constructed with a narrow axial support flange to cause the body of the wheel to be formed at its radially inner extent with a correspondingly narrower tire body width tapered axially inwardly from the opposite sides to cooperate in providing a low moment of inertia. In one embodiment the tire body is configured with a narrow crown to cooperate with the low moment of inertia to facilitate shifting of the wheel quickly from a turning position inclined in one direction to a position inclined in the opposite direction.

[0010] In one embodiment, the lightweight hub is formed with a transverse, annular bearing housing with oppositely opening bearing glands for insertion of a pair of bearings to mount on a skate wheel axle. The hub projects radially outward from this bearing housing in the form of an annular support disk which carries the annular support flange. The tire is mounted on the annular support flanges and encases a stabilizer ring that projects radially outwardly from the support flange. The radial stabilizer ring projects radially outwardly to cooperate in forming a tall profile projecting radially outwardly into the tire body to provide support under the tread to decrease deflection and rolling resistance, thus providing greater straight-line speed. The radial stabilizer ring profile is relatively thin, allowing a greater amount of the softer tire material on the sidewalls, promoting increased grip and maneuverability.

[0011] In one embodiment the hub is sectioned into two axial flanking sections which join to form the hub itself. The annular support disk may be formed with an annular tube or shell configured with the lightening cavity. Such shell and/or hubs may be sectioned to provide for ease of fabrication in sections to be joined by a mechanical joint and/or adhesive.

[0012] In one aspect of the present invention, a urethane wheel is formed by a hub fitting is constructed of first and second annular sections forming a bearing housing and an annular lightening shell concentric about the housing, with the shell being formed of confronting half tube walls terminating in concentric confronting edges, the edges including interfitting tongue and grove joint, constructed to snap together.

[0013] The present invention contemplates a cost effective method for manufacturing the wheel. The method employs a mold having annular upper and lower mold sections and a back pin section. The lower mold section is formed with an annular mold cavity section defining a central annular lower hub cavity for receiving a hub formed with the annular support flanges of a predetermined axial width and an outer lower tire body cavity section. The upper mold section is constructed to mate with the lower mold section and cooperates therewith to form a tire body cavity section curving radially inwardly and axially outwardly from a tread crown to form a maximum tire body width greater than the predetermined axial width of such support flanges, the top cavity wall projecting radially inwardly and axially outwardly to terminate in an annular sprue wall. The tire body cavity section is constructed so the lower annular support flange of the hub sealingly engages the wall of such cavity section and the back pin is constructed with an annular sealing lip to form a seal against the upper annular support flange on such hub. The pin further forms a portion of the tire's profile, curving upwardly from the annular support flange to terminate in a back pin sprue wall spaced radially inwardly from and concentric with the upper mold section sprue wall to form an annular sprue inlet for receipt of prepolymers, curatives and pigment additives.

[0014] To form a wheel, a preformed hub is placed in the lower mold section, the upper mold section is then positioned on the lower mold section, and the back pin is engaged with the hub. Prepolymers, curatives and pigment additives which will interact to form a polyurethane are then introduced through the sprue inlet to fill the tire body cavity and surround and bond to the annular support flanges and tire support rim portions of the hub to cooperate in forming a wheel. The wheel is then removed from the mold and trimmed.

[0015] As will be apparent to those skilled in the art for the sectioned hubs the separate sections therein may be fabricated separately and joined together to complete the finished hubs for receipt of the urethane tire material to be molded therein.

[0016] Other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a side view of the wheel of the present invention;

[0018]FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1;

[0019]FIG. 3 is a side view of a hub included in the wheel shown in FIG. 1;

[0020]FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 3;

[0021]FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 3;

[0022]FIG. 6 is a cross-sectional view of a prior art tire casting mold;

[0023]FIG. 7 is a cross-sectional view of the tire casting mold utilized to make the wheel of the present invention;

[0024]FIGS. 8 and 9 are diametrical sectional views of first and second hub sections of a second embodiment of the wheel of the present invention;

[0025]FIG. 10 is a diametrical sectional view of the sections shown in FIGS. 8 and 9 joined together;

[0026]FIG. 11 is a diametrical sectional view similar to FIG. 10 but showing a tire body mounted on the hub;

[0027]FIGS. 12 and 13 are diametrical sectional views of first and second hub sections of a third embodiment of the wheel of the present invention;

[0028]FIG. 14 is a diametrical sectional view showing the sections of FIGS. 12 and 13 joined together;

[0029]FIG. 15 is a diametrical sectional view of the hub shown in FIG. 14 but with a tire body mounted thereon;

[0030]FIGS. 16 and 17 are cross-sectional views of first and second annular tubular shell sections of a fourth embodiment of the wheel of the present invention;

[0031]FIG. 18 is a cross-sectional view showing the annular tubular shell sections of FIGS. 16 and 17 joined together; and

[0032]FIG. 19 is a diametrical sectional view in reduced scale showing shell sections of FIG. 18 incorporated in a hub with a tire body mounted thereon.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0033] Performance is a key requirement for in-line skaters, especially those engaged in high speed competitions such as roller hockey and racing. Manufacturers have developed wheels of various profiles and hardness values to enhance sliding, gripping, maneuverability, speed, comfort and durability depending on the user's desire and skill level. It has been determined that large diameter wheels with minimal tire flexing to reduce rolling resistance are superior when speed is desired. Recreational skaters generally prefer smaller diameter wheels with shock absorbing properties while those doing stunts such as rail slides prefer wheels of an even smaller diameter and high hardness value. Two general types of wheels have emerged over the past two decades to meet these diverse needs, those containing pneumatic tires made by casting urethane around an annular bladder, and those with solid tires made by casting or injection molding urethane in the desired shape around a hard urethane or nylon hub. To optimize speed and maneuverability, a large diameter, lightweight, firm wheel with the capability for flexibility to engage more sidewall material while maneuvering is desirable. The present invention provides such a tire and a cost effective method for its manufacture.

[0034] Referring to FIGS. 1 and 2, the in-line roller skate wheel 20 of the prevent invention is of the two-piece construction including, generally, a hub 30 and a solid tire body 50. The hub 30 is formed with a cylindrical bearing housing 31 including oppositely opening bearing glands 32 and 33 for insertion of a standard set of bearings to mount the wheel on an axle. Projecting radially outwardly from the bearing housing 31, an annular stabilizer disk 34 supports a pair of annular support flanges 37 and 38 projecting in the opposite axial directions. Such annular support flanges 37 and 38 cooperate with the annular stabilizer disk 34 in forming a tire body support that is advantageously narrow in axial cross section. The annular stabilizer disk 34 projects radially outwardly beyond the annular support flanges 37 and 38 to form a radial stabilizer ring 39 which cooperates to provide radial, circumferential, and axial support and stability to the tire body 50 during skating maneuvers. Such ring is formed with through axial bores 40 spaced equidistant thereabout. As seen in FIG. 2, the annular stabilizer disk 34, annular support flanges 37 and 38, and radial stabilizer ring 39 cooperate to form a generally cruciform shape in transverse cross section.

[0035] Referring still to FIG. 2, the urethane tire body 50 is formed with radially inwardly facing flanking bearing surfaces defining beads 54 and 55 that rest on the radially outwardly facing surfaces of the respective annular support flanges 37 and 38 and the urethane material can be seen to encapsulate the radial stabilizer ring 39 and fill the through-bores 40 to solidly anchor the tire body 50 to the hub 30. The short axial length of the annular support flanges 37 and 38 and relatively large diameter of the radial stabilizer ring 39 causes the tire body 50 to be formed with a narrow rounded central tread area 56 and the side walls to then angle radially inwardly and axially outwardly to a bulbous major width at line B-B from where such walls curve radially and axially inwardly toward one another defining the transition wall sections 51 and 52. The exterior contour of such tire in the axial cross section then cooperates in forming a shape simulating that of the profile of the glass portion protruding from the metal socket of a Christmas tree light bulb. This profile allows the skater to more quickly transition from one side of the wheel 20 to the other, increasing responsiveness. The narrower cross section of the tire body, and short axial length of the annular support flanges 37 and 38 causing the decreased-in-width cross section radially inwardly from the major diameter B-B, serve to provide for a lightweight polyurethane tire body 50. It will be appreciated that in some embodiments of the present invention the disk 34 may project radially outwardly to the diameter of the respective flanges 37 and 38.

[0036] Referring to FIGS. 3-5, the hub is formed with radial stiffening webs 36 spaced at 90 degree increments on opposing axially outwardly facing surfaces of the annular stabilizer disk 34 radially inwardly of the respective annular support flanges 37 and 38. The edges of such stiffening webs 36 curve axially inwardly and radially outwardly from the axially outward edge of the bearing housing 31 to blend into the annular stabilizer disk 34 at its juncture with the annular support flanges 37 and 38. The stiffening webs provide support to the annular stabilizer disk 34 and allow a thinner, lighter disk than would otherwise be able to support the stresses created by skating.

[0037] The hub 30 is formed as a single piece to simplify wheel manufacture and incorporates several weight saving features as can be appreciated in FIGS. 3-5. Sculpturing 35 on the axially outward faces of the bearing glands 32 and 33 reduces weight and provides the added benefit of exposing a larger portion of the bearings to air to improve cooling. The disk 34 is formed with a plurality of annular, transverse through lightening bores 41 are disposed in an annular arrangement on a diameter smaller than that of the flanges 37 and 38.

[0038] The bearing housing 31, annular stabilizer disk 34, radial stabilizer ring 39, and tire body 50 are centered on the wheel centerline A-A shown in FIG. 2. The bearing glands 32 and 33 are axially opposing and equidistant from the centerline as are the stiffening webs 36 and the annular support flanges 37 and 38. An alternate embodiment, not shown, can be formed with the radial stabilizer ring 39 advantageously offset from this centerline to provide different degrees of stiffness on the two sides of the wheel for special maneuvering capability.

[0039] In the preferred embodiment shown in FIGS. 1-5, the hub 30 is formed with an outer radial diameter of approximately 2.150 inches at the distal radial edges of the radial stabilizer ring 39. The annular support flanges 37 and 38 have an overall axial width of approximately 0.560 inches and are formed such the outer radial diameter of their radially outwardly facing surface is approximately 1.500 inches at their axially outermost point. The bearing glands 32 and 33 are formed with an inner radial diameter of approximately 0.627 inches to accept a relatively small diameter bearing (not shown) known in the trade as a micro bearing. The bearing glands 32 and 33 may also be formed with an inner radial diameter of approximately 0.866 inches to accept the larger standard bearing. The tire body 50 is formed with an outer radial diameter of approximately 2.835 inches and curves radially inwardly and axially outwardly from the outer diameter to an axial width of approximately 0.850 inches and then curves radially and axially inwardly to an axial width of approximately 0.560 inches where it joins the annular support flanges 37 and 38. The maximum axial width, shown by the line B-B in FIG. 2, is located approximately 0.97 inches radially outward from the radial centerline of the hub. It will be appreciated that the wheel of the present invention is ideally about 0.850 inches wide but many vary in maximum width up to substantially less than the traditional width of 0.965 inches, typically 0.900 inches or less.

[0040] A method for manufacturing the wheel of the present invention uses a three piece mold as shown in FIG. 7. For comparison, a prior art method for manufacturing a wheel is shown in FIG. 6 to demonstrate the advantages of the present method.

[0041] Referring now to FIG. 6, one sees an example of a prior art urethane casting mold 60. The lower mold section 61 is formed with an annular upwardly opening cavity and is positioned horizontally to accept a conventional cylindrical hub 64 in a manner similar to the present invention. The annular upper mold section 62 is then positioned atop the lower mold section 61 and cooperates with it to form an annular cavity in the desired shape a tire to be casted. An axial back pin 63 is then inserted into the top end of hub 64 and more specifically into an extended skirt 65 on the hub 64 to block flow of liquid urethane into the hub spokes and bearing housing during the casting process. It will be appreciated by one skilled in the art that the back pin 63 forms no part of the cavity defining the tire profile. After casting, the wheel is removed from the mold 60 and the hub skirt 65 and excess urethane must be trimmed.

[0042] Referring to FIG. 7, a mold 70 is shown that may be used to make the wheel 20 of the present invention. In describing the wheel 20, hub 30, tire body 50, and mold 70, the term lower will refer to the lower one-half axial side of the wheel and, the term upper to the upper one-half axial side of the wheel. As can be seen, the mold 70 may include, generally, a lower mold section 71, an upper mold section 72, and a central back pin 73. The lower mold section 71 is formed with an upwardly opening cavity configured to cooperate with a downwardly opening annular cavity formed by the combination of the upper mold section 72 and back pin 73 to define a major portion of the desired tire body profile.

[0043] The lower mole section 71 is formed with an upwardly opening central annular cavity well 74 configured to complementally receive the axially lower portion of the bearing housing 31 and surrounding an axial centering post 75 configured to be complementally received in telescopical relationship in the lower end of such bearing housing. The radial outer walls forming the central annular cavity well 74 slope axially upwardly radially and outwardly to form an annular sealing lip 76 configured to be engaged telescopically in fluid light relationship on the radially inner side of the annular support flange 37. The lower mold section 71 is then formed with a tire body wall concentric about the well 74 which curves radially outwardly and axially downwardly from the annular sealing lip 76 to form a narrowing section 77 forming the shape of the narrowing transition wall section 51 of the tire body and configured to have the axial edge of the flange 37 nested thereagainst. The lower mold section 71 then slopes axially downwardly to a maximum tire diameter and then slopes axially upwardly and radially outwardly to complete the form of one half the tire body terminating at a central separation line disposed at the crown of the tire body.

[0044] As will be appreciated by those skilled in the art, the upper and lower mold sections 72 and 71 are configured to register together. To this end, the lower mold section is formed with a raised rib 78 and an annular radially outwardly opening notch for receipt of a downwardly projecting annular ring 79 formed about the periphery of the upper mold section 72.

[0045] The upper mold section 72 is donut shaped and is configured with an arcuate axially downwardly and inwardly facing curved annular cavity surface 80 configured to cooperate with the radially distal portion of the lower cavity section to form the opposite tread walls of the tire body.

[0046] The back pin 73 is configured with a downwardly projecting, axial, stepped centering post 81 confronting the post 75 and configured to be complementally received in the upper end of the bearing housing 31 of the hub 30 to center such pin therein. Such back pin is formed with a downwardly opening annular well 82 configured to complementally receive the axially upper portion of the bearing housing 31. The back pin 73 is further formed with a downwardly projecting annular, concentric sealing lip 83 for sealing against the radially interior side and axial end of the annular support flange 38 of the hub 30 to seal against escape of liquid polyurethane. Such back pin is then formed with a tire body wall which slopes radially outwardly and axially upwardly from the annular sealing lip 83 to form an annular cavity narrowing section 84 configured to form the shape of the narrowing transition wall section 52 of the tire body.

[0047] Such back pin is formed with a major diameter annular wall 85 is configured to cooperate with the inner annular wall 86 of the upper mold section 72 to form an annular sprue to accommodate the pouring of prepolymers, curatives and pigment additives during the manufacturing process.

[0048] It will be appreciated that the back pin 73 is designed to provide a cost effective method of wheel 20 manufacture. In the prior art, as shown in FIG. 6, the axial width of the urethane tire is constant as it approaches the hub 64. Conventionally, the back pin 63 merely acts as a plug and necessitates a cylindrical skirt 65 on the hub to seal liquid urethane from flowing into the hub and bearing housing. The opposite walls of tire body 50 of the present invention curves, arially and radially inwardly in the narrowing section 77 in to meet the hub 30. As shown in FIG. 7, the design of the present invention back pin is unique in that the annular sealing lip 83 forms an effective seal against the hub 30 without the need for a skirt. This back pin design is further unique in that it also forms a portion of the urethane tire profile that tucks in on the back side of the wheel.

[0049] To manufacture an in-line roller skate wheel using the techniques and designs of the present invention, a mold 70 of the desired wheel profile is first selected. The appropriate hub 30 is then placed in the lower mold section 71 with the centering post 75 complementally received in the lower end of the hub's bearing housing 31 and the hub's annular support flange 37 resting squarely on the annular sealing lip 76 of the lower mold section 71. The upper mold section 72 is then placed on the lower mold section 71 such that their surfaces are flush with one another and the raised rib 78 and annular ring 79 are in registration around the entire perimeter. The back pin 73 is then placed on the hub 30 such that the back pin centering post 81 is complementally received in the upper end of the hub bearing housing 31 and the back pin annular sealing lip 83 engages the upper annular support flange 38 around its entire perimeter. The major diameter of the upper mold section annular wall 85 and back pin inner annular wall 86 now cooperate to form an annular sprue inlet. Prepolymers, curatives and pigment additives which will interact to form a polyurethane are then introduced through the sprue inlet to fill the tire body cavity formed by the mold 70 and surround and bond to the radially outward surface of the annular support flanges 37 and 38 to cooperate in forming a wheel. One polyurethane suitable for this application is sold by B. F. Goodrich under the trade designation ESTALOC®. In some applications it may be desirable to incorporate reinforcing fibers such as those included in grade No. 59300. The back pin 73 and upper mold section 72 are then removed, the wheel 20 is removed from the lower mold section 71, and excess urethane is trimmed from the wheel. The wheel is then ready for use on a skate.

[0050] In use, a set, generally four, of the light weight, low inertia wheels of the present invention is mounted on each of a pair of in-line roller skates. The performance advantages provided by these wheels will be appreciated by reviewing maneuvers a skater advances through in a typical competition and examining how the wheel's features cooperate to improve the skater's competitive edge. Initially, the skater must accelerate. In this phase, the thin tire body profile and curving provide the tire opposite side walls radially inwardly toward one another to meet the respective ends of the short annular support flanges presents the benefit of reduced mass to form low inertia wheels. This allows rapid angular acceleration of the wheels themselves and the light weight of the skates to allow for quick strides, both contributing to rapid buildup of the skater's speed as the skater then transitions into the high speed phase straight line speed becomes of paramount importance. The tall profile of the radial stabilizer ring causes it to project well into the tire body material to provide greater support to the tread area to decrease deflection and consequent rolling resistance. The skater will now benefit from the relatively large light weight diameter wheel to further enhance speed. In addition to high speed, a competition such as ice hockey also requires great maneuverability on the part of the skater. Quick turns and rapid deceleration and acceleration are critical to success. The relatively thin profile of the radial stabilizer ring provides for a significantly greater amount of the softer tire body on the opposite sides thereof to promote increased function and grip in the sidewall area for improved maneuverability and braking during turning maneuvers. The low inertia of the wheels also improves deceleration allowing them to stop spinning more quickly. As the competition goes on, it will be appreciated that the light weight skates require less expenditure of energy by the skater as the mass to be accelerated and decelerated in each stride is reduced This allows better sustained performance and more enjoyment on the part on the skater.

[0051] Referring to FIGS. 8-11, a second embodiment of the wheel of the present invention includes, generally, first and second cylindrical hub sections 102 and 104 which, when joined, form an axial hub 106. The hub section 102 is formed with an axial cylindrical female tube 108 configured with a cylindrical bearing gland 110. Radiating outwardly from such female tube 108 is an annular support disk section 112 supporting an annular load bearing support flange 114 projecting axially to the left (FIG. 8) and formed with a radially outwardly facing annular support seat 116. The disk section 112 is formed at its radially outer extremity with an annular half tube shell section 118 to cooperate in defining a lightening cavity. The shell section 118, is, in cross section, in the form of an arcuate half cylinder and opens to the right as viewed in FIG. 8 and is formed with a pair of radially spaced apart concentric edges undercut externally to form oppositely facing circumferential notches having respective projecting circumferential lips defining tongues 120 and 124. The hub section 102 is formed on its interior face with an annular interface configured with a circular recess 128 having the same diameter as the outer diameter of the interior for a tongue 124.

[0052] The second hub section 104 is configured with an axial bearing tube section 130 formed with a male tube section 132 for telescopical receipt into the right end of the socket 110 and to define interiorly on the right-hand extremity a bearing gland 134. An annular support disk section 136 radiates outwardly from the tube 132 to be sandwiched against the disk section 112 and is formed medially with an annular load bearing flange 138 projecting axially to the right (FIG. 9) having a radially outwardly facing annular seat 140 aligned axially with the seat 116. The disk section 136 is formed at its radially outer extremity with a half tube arcuate shell section 144 constructed to cooperate with the shell section 118 to form an annular, tube shaped shell. The wall of such shell section 144 terminates in concentric edges which are undercut internally to provide annular notches defining respective concentric grooves 148 and 149 configured to receive in inter-fitting relationship the respective tongues 120 and 124 for nesting therein. (FIG. 10) The undercut defining the groove 149 (FIG. 9) is of the same diameter as the diameter of the recess 112 (FIG. 8) to thus form a raised boss to be registered in such recess on assembly (FIG. 10).

[0053] In assembly, it will be appreciated that the axial sections 102 and 104 may be molded separately and may be joined by telescoping the male tube 132 into the female socket 110 as shown in FIG. 10 thus causing the raised boss defined by the undercut 149 in the hub section 104 to be nested in the recess 112 (FIG. 10) and the respective tongues 120 and 124 to be received in sliding relationship within the respective grooves 148 and 149. In practice, such tongues are received in friction fit within such grooves and may be further secured therein by adhesive or other bonding material which is well known to those skilled in the art.

[0054] The hub, when assembled and joined, can thus be casted with a tire body 154 thereabout in a manner similar to that shown for the wheel depicted in FIG. 7. The tire body 154 is constructed with a narrow crown 156 defining a tread surface and walls which slope radially inwardly while angling axially outwardly to a major thickness 158 from where they curve or slope radially inwardly axially toward one another to join at the opposite outer extremities of the respective support flanges 114 and 138. The wheel body 154 thus forms beads 162 and 164 which nest on the respective seats 116 and 140. The construction thus affords a narrow lightweight wheel body which has a relatively narrow width and includes an annular void in the shell sections 118 and 144 to provide a relatively low mass to thus facilitate high performance skating.

[0055] Referring to FIGS. 12-15 a third embodiment of the wheel apparatus of the present invention is similar to that shown in FIGS. 8-11 and includes hub sections generally designated 170 and 172. The hub section 170 is formed with an integral cylindrical bearing housing generally designated 176 configured with axially outwardly opening bearing glands 178 and 180. Radiating outwardly from the tube 176 is a support disk 182 which mounts on the opposite sides thereof respective support flanges 184 and 186. Formed at the radially outer extent of such support disk is an annular half tube shell section 190 which opens to the left as viewed in FIG. 13 and terminates in concentric edges which are undercut interiorly to form circumferential lips 192 and 194 spaced radially to form interior groove 198 and 199.

[0056] The second hub section 172 is also annularly shaped in the form of a half annular tube opening to the right and formed with radially spaced apart concentric edges undercut exteriorly to leave annular lips defining tongues 202 and 204 configured to be complementally received in the respective annular grooves 198 and 199 (FIG. 14).

[0057] When joined together as shown in FIG. 14, such hub 169 forms a medial joint generally designated 208 which may be bonded by any well-known adhesive. The hub may then be placed in a mold like that shown in FIG. 7 and the tire body, designated 212, molded there around.

[0058] A fourth embodiment of the wheel of the present invention (FIGS. 16-19) is similar to that shown in FIGS. 8-11 except the two annular hub sections, generally designated 220 and 230, are joined together to form hub fitting 240 by means of a mechanical snap joint rather than just friction and/or adhesives. Such hub sections cooperate to form an annular disk 222 and annular support flanges 224 and 226 which combine to form an axial width less than the preferred maximum width of the tire body 242 so that the opposite side walls of such body curve axially and radially inwardly from the major tire thickness to the opposite ends of such flanges. Hub section 220 is formed at its radially outer extremity with an annular half tube shell section 221 which opens to the right as viewed in FIG. 16 forming edges which are undercut interiorly to define concentric annular lips 222 and 225 formed on their confronting surfaces with respective V-shaped tongues 232 and 234.

[0059] The section 230 is configured with a half tube annular shell 241 terminating in concentric edges defining circumferential lips 242 and 244 which are undercut externally to form respective opposite outwardly facing concentric V-shaped grooves 246 and 248 configured to compliment the shape of such of the respective tongues 232 and 234. It will be appreciated that when the hub sections 220 and 230 are assembled, they may be mated together in a fashion similar to that for the hub sections shown in FIGS. 8 through 11. As the sections are brought together, the respective half tube shell sections 221 and 230 will flex slightly to allow the respective V-shaped tongues 232 and 234 to cam over the respective retainer ribs 247 and 249 to then snap into place in the respective groove 246 and 248 thus retained securely therein by the mechanical interlock. It will be appreciated that the arrangement of the tongue and groove joint structure can be configured such that there is an interference fit to provide for a mechanical lock. If desired adhesives may be added but, in some instances, the mechanical interference between the retainer ribs 247 and 249 and the tongues 232 and 234 will be such that, when constrained within the body of the tire 242 will afford sufficient locking force to maintain the hub sections 220 and 230 locked together under normal use.

[0060] It will be appreciated that the tire body 242 may be casted about the distal portion of the disk 222 in a fastening fashion similar to that described above to provide for a maximum width of the tire body of about 0.850 inches or possibly slightly more and then curve radially and axially inwardly as shown in FIG. 19 to the opposite ends of the respective support flanges 224 and 226 such that the inwardly facing support surfaces 252 and 256 nest on such flanges thus affording adequate support and making full benefit of the diminished tire body mass radially interior of the major width of such wheel body.

[0061] It will be appreciated that for the wheel shown in FIGS. 16 through 19, the hub sections 220 and 230 have broad application and have utility in providing secure structure and lightening benefits for polyurethane wheels of many different configurations and widths. One particular utility is in the fabrication of the above-described narrow wheels described above.

[0062] From the foregoing, it will be apparent that the narrow profile of the present invention provides a lightweight wheel that presents high performance characteristics while exhibiting a relatively low moment of inertia. The wheel has a pronounced pointed profile allowing for the greatest flex of the sidewalls and a small but firm contact patch in the center of the tire. These features promote high speed and maneuverability on tiled surfaces and the wheel is well suited for indoor hockey. It will however be appreciated that with minor alterations of the mold a slightly wider profile can be cast for indoor hockey on Roll-On™ or maple wood flooring. A full wrap profile can also be formed to place a greater amount of urethane on the tire to maximize durability for outdoor use. Other enhancements could include shims placed on the sides of the tire support rim to increase the rigidity of the wheel, decreasing the sidewall grip but increasing wheel speed.

[0063] It will therefore be appreciated by those skilled in the art of in-line skate wheels that the invention as illustrated and described herein is the preferred embodiment and that changes in shape, materials, tire profile and tread design may be made without departing from the spirit and scope of the invention. It is also appreciated by those skilled in the art of skate wheels that the designs and methods of this invention could be applied to the production of scooter wheels. Accordingly, it is not intended that the invention be limited except by the appended claims. 

What is claimed is:
 1. A narrow profile lightweight urethane in-line skate wheel comprising: a hub formed with a cylindrical bearing housing for mounting on bearings and including a radially outwardly projecting support disk; annular support flanges projecting axially outwardly on opposite sides of said disk to form respective radially outwardly facing load support surfaces and cooperating to a predetermined combined axial width; an annular urethane tire body mounted on said load bearing flanges and encasing the axially opposite sides of the radially outward portion of said disk, said tire body being configured with an annular tread section having oppositely disposed tread walls sloping axially outwardly and radially inwardly from a major radial diameter to a maximum axial width greater than said predetermined axial width; and said tire body further including a narrowing body section interposed between said tread section and said load bearing surface and configured with opposite narrowing walls sloping axially and radially inwardly toward one another from said maximum axial thickness to the opposite ends of the respective said flanges and configured with radially inwardly facing beads abutting the respective said support surfaces.
 2. The wheel of claim 1 wherein: said opposite narrowing walls curve radially inwardly and axially inwardly toward one another.
 3. The wheel of claim 1 wherein: said tire body is formed with said maximum axial width less than 0.965 inches.
 4. The wheel of claim 1 wherein: said tire body is formed with said maximum axial width substantially to 0.850 inches.
 5. The wheel of claim 1 wherein: said tire body is formed with said maximum axial width no greater than to 0.900 inches.
 6. The wheel of claim 1 wherein: said bearing housing has an axial width greater than said predetermined load bearing flange axial width.
 7. The wheel of claim 1 wherein: said tire body is molded on said hub.
 8. The wheel of claim 1 wherein: said support disk projects radially outwardly a distance from said load bearing surface to project at least to the radial center of said tire body.
 9. The wheel of claim 1 wherein: said tire body section is oval in transverse cross section.
 10. The wheel of claim 1 wherein: said tire body is Christmas tree bulb shaped in transverse cross section.
 11. The wheel of claim 1 wherein: the said predetermined combined axial width is 0.560 inches.
 12. A lightweight narrow in-line roller skate wheel comprising: a hub constructed with a bearing housing and including a radially projecting annular support disk; a pair of annular load bearing flanges projecting axially on the opposite sides of said disk and configured with respective radially outwardly facing load support surfaces; an annular urethane tire body molded about the radially outer extent of said support disk and nesting against and bonded to said load bearing surface, said tire body being formed in its radially outer extent with an oval in cross section annular tread section having a maximum axial width greater than the axial width of said load bearing flange, said tire body further including a narrowing body section intermediate said tread section and said load bearing flange and formed with opposite side walls curving radially and axially inwardly toward one another to join the opposite axial ends of the respective said load bearing flanges.
 13. A narrow lightweight in-line roller skate wheel comprising: a hub including an annular housing and a centrally disposed radial disk, said hub including annular support flanges on the opposite sides of said disk cooperating to form a combined overall axial length no greater than 0.560 inches; a urethane tire body formed about the radially outer extent of said disk, configured with a tread crown and sloped side walls sloping radially inwardly and axially outwardly from said tread crown to a maximum width of 0.850 inches, said side walls then sloping radially and axially inwardly toward one another to terminate at the respective axial ends of the respective said flanges, said body being further formed with radially inwardly facing bearing surfaces nested on the respective said support flanges.
 14. A narrow lightweight in-line roller skate wheel comprising: a hub including an annular housing and radial support disk; an annular urethane tire body on said disk, having a maximum axial width less than 0.965 inches and including narrowing means having opposite side walls sloping radially and axially inwardly toward one another to terminate in a narrow width less that said maximum axial width; said hub including an annular support means mounted on said disk and supporting said tire body.
 15. The method of manufacturing an in-line roller skate wheel including the following steps: selecting a hub with an annular bearing housing having a pair of annular load bearing flanges of a combined predetermined axial width; selecting a mold having upper and lower mold sections, said lower mold section configured with an annular mold cavity section defining a central lower hub cavity section and an outer lower tire body cavity section, said tire cavity section including a bottom wall extending radially outwardly from said hub section and formed with a downwardly and outwardly sloped narrowing section extending to a bottom maximum width ring and then turning radially outwardly to curve upwardly and radially outwardly to a juncture surface, said upper mold section being constructed to mate with said lower mold section and formed with a downwardly opening tire body cavity section having a wall aligned with said terminus and curving upwardly and radially inwardly to a top maximum width ring spaced from said bottom maximum width ring to form a maximum body width greater than said predetermined load bearing flange axial width and projecting radially inwardly to terminate in an annular sprue wall; placing said hub in said lower hub cavity section; positioning said upper mold section on said lower mold section; selecting a back pin and engaging it with said hub to position an annular back pin sculpture shoulder angling upwardly and axially outwardly from said load bearing flange to terminate in an annular sprue wall spaced annularly from said first sprue wall to form an annular sprue inlet; introducing prepolymers, curatives and pigment additives through said sprue inlet to fill said body cavity and surround and bond to said support disk to cooperate in forming a wheel; removing said back pin and said upper mold section; and removing and trimming said wheel.
 16. The method as set forth in claim 15 wherein: said back pin is selected having an annular downwardly opening cavity for nesting therein of the upper axial side of said hub.
 17. The method as set forth in claim 15 wherein: said back pin is selected with a sealing lip disposed radially inwardly of said sculpture wall and configured to sealingly engage said load bearing flange.
 18. The method of claim 15 wherein: said hub is selected of first and second sections having first and second joint sections and includes the steps of: joining said first and second sections before placing said hub in said mold.
 19. The method of claim 15 wherein: the step of selecting said hub includes selecting said first and second sections of the type cooperating to, when joined, form an annular shell disposed concentrically thereabout to define a lightening cavity; and the step of placing said hub in said mold includes placing said annular shell in said tire body section.
 20. An annular mold for molding a sculptured in-line roller skate wheel tire body to a wheel hub having an annular bearing housing and radially outwardly projecting annular mounting disk formed medially with an annular load bearing flange having a predetermined axial width and terminating in, when said hub is laid on its side, respective lower and upper annular edges; said annular mold including upper and lower mold sections connected together and severable along a mold mating surface; said lower mold section being configured with a lower mold cavity including an annular hub mold section for receiving one axial side of said hub and configured with a radially exterior wall terminating at a top edge in an annular sealing lip configured to engage said lower edge of said load bearing flange, said lower mold section being further formed with a lower mold section tire body cavity circumscribing said lower mold hub section cavity and formed with an annular bottom wall curving downwardly and outwardly from said sealing lip to then turn and project radially outwardly and curve upwardly and radially outwardly to terminate in an annular terminus at said mating surface; said upper mold section being configured with an upper section mold cavity cooperating with said hub mold section and said tire mold cavity and having an upper wall curving upwardly and axially inwardly from said terminus to terminate in an annular sprue wall edge; and a back pin constructed with a downwardly opening hub cavity for, when said hub is in said lower mold cavity, receipt of the upper portion of said hub and configured with an annular sealing lip for sealingly engaging said upper edge of said load bearing flange, said back pin further including a sculpture cavity surface angling upwardly and outwardly from said sealing lip to terminate in a back pin sprue wall spaced radially inwardly from said first sprue edge to form a sprue opening for receipt of prepolymers, curatives and pigment additives.
 21. A mold for molding a soft urethane tire body to a hard urethane hub to form a urethane wheel configured with sculptured said tire body section having axially opposite sides angling axially outwardly from a mounting flange on said hub to angle axially and radially outwardly and to then curve radially outwardly and axially inwardly toward one another forming a tread surface, said mold apparatus comprising: a lower mold section having a lower hub cavity for nesting therein of said hub to position said hub's radial plane in a generally horizontal plane; said lower hub section further including a lower tire body cavity concentric about said lower hub cavity configured to form one side wall of said tire body; and an annular upper mold section and central back pin configured to cooperate in forming an upper mold tire body cavity section cooperating with said lower hub cavity and tire body cavity to form the shape of said tire body about said hub, said back pin being configured to engage the top side of said hub and formed with a downwardly and outwardly facing sculpture surface to cooperate in forming the second side wall of said tire body.
 22. The wheel of claim 1 wherein: said tire body is formed with an annular lightening cavity.
 23. The wheel of claim 1 that includes: an annular shell embedded in said tire body and formed with an annular lightening cavity.
 24. The wheel of claim 1 that includes: an annular lightening shell mounted on said support disk, embedded in said tire body and formed with a lightening cavity.
 25. The wheel of claim 1 wherein: said hub is formed with first and second axial sections disposed on opposite sides of a central radial plane through said hub, said hub further including a joint for connecting said axial sections together.
 26. The wheel of claim 2 wherein: said joint includes male and female joint sections.
 27. The wheel of claim 26 wherein: said joint includes an adhesive.
 28. The wheel of claim 25 wherein: said first and second axial sections are formed with first and second annular support disk sections joined together to form said support disk and respective first and second annular shell sections joined together to form an annular shell defining a lightening shell configured with an annular lightening cavity.
 29. The wheel of claim 24 wherein: said lightening shell includes said first and second annular shell sections joined together by respective annular joints.
 30. The wheel of claim 29 wherein: said joints are formed by an interference fit of annular tongue and groove structures formed in said annular shell sections to cooperate in forming the respective said joints in an interlocked mechanical construction.
 31. The wheel of claim 1 wherein: said hub is formed with a first hub section including said cylindrical bearing housing, said radially outwardly projecting support disk, said annular load bearing flanges, and an annular shell section disposed on one axial side and formed radially outward from said support disk; said hub is further formed with a second section consisting of an annular shell section radially concentric with the annular half shell section of the said first hub section and disposed on the opposite side of a central radial plane through said hub; said hub includes a joint for connecting said annular shell sections together; and said annular shell sections are joined together to form an annular shell defining a lightening shell configured with an annular lightening cavity.
 32. The wheel of claim 31 wherein: said joint includes male and female joint sections.
 33. The wheel of claim 31 wherein: said joint includes an adhesive.
 34. The wheel of claim 31 wherein: said joint is formed by an interference fit of annular tongue and groove structures formed in said annular shell sections which cooperate to form said joint in an interlocked mechanical construction.
 35. A narrow profile lightweight urethane in-line skate wheel comprising: an annular urethane tire body formed with a radially distal narrow tread crown and having side walls tapering radially inwardly and axially outwardly away from one another to a major thickness and then tapering radially and axially inwardly toward one another to terminate in respective radially inwardly facing beads; and hub means including a radially outwardly projecting support disk formed with annular support flange means having radially outwardly facing tire body bead receiving means engaging said tire body bead means.
 36. The wheel of claim 35 wherein: said hub means is constructed of first and second sections joined together by joint means.
 37. A urethane in-line skate wheel comprising: a hub fitting forming a bearing housing, a concentric lightening shell spaced radially therefrom and an annular disk interposed between said housing and shell; said hub fitting being formed by first and second annular hub sections configured with respective first and second half tubes cooperating to form said shell and terminating in respective confronting concentric edges, said edges being formed with respective interfitting tongues and grooves configured to fit frictionally together in interlocking relationship; and a urethane tire body formed about said shell and disk.
 38. The tire set forth in claim 37 wherein: said tire body has a maximum width less than 0.965 inches and is formed with the opposite side walls sloping axially and radially inwardly toward one another from said maximum width to form a radially inwardly facing support surface of a predetermined axial width less than said maximum width; and said hub fitting includes annular flanges carried on the opposite sides of said disk, intermediate said housing and shell and having a combined axial width equal to said predetermined axial width.
 39. The wheel set forth in claim 37 wherein: the respective said edges of said second tubes are constructed with respective annular retainers; and the respective first tubes are constructed with said tongues configured to, when said tubes are joined together, be retained frictionally behind the respective said retainers.
 40. The wheel as set forth in claim 39 wherein: the respective said tongues are configured to be, upon joinder of said tubes, flexed relative to respective said retainers to ride over the respective said retainers and be mechanically retained there behind in the respective said grooves. 